Neisseria gonorrhoeae with Reduced Susceptibility to Azithromycin — San Diego County, California, 2009

A single 2 g dose of azithromycin effectively treats genitourinary infections caused by susceptible Neisseria gonorrhoeae and has been used to treat uncomplicated gonorrhea in persons with cephalosporin allergy. However, azithromycin is not recommended as monotherapy because of concern over the emergence of resistance. Instead, a 1 g dose of azithromycin is recommended as a component of dual therapy for gonorrhea, in conjunction with a cephalosporin (i.e., 250 mg of ceftriaxone or 400 mg of cefixime, if ceftriaxone is not an option). During January 1992--July 2009, of 87,566 N. gonorrhoeae isolates tested for azithromycin susceptibility by CDC's national Gonoccoccal Isolate Surveillance Project (GISP), only 39 (0.04%) had minimum inhibitory concentrations (MICs) ≥8 µg/mL (including 25 with 8 µg/mL and 14 with 16 µg/mL), indicating reduced susceptibility; none of the isolates were collected in San Diego County, California (CDC, unpublished data, 2011). During August--October 2009, five of 55 (9.1%) N. gonorrhoeae isolates obtained from men with symptomatic urethritis tested at San Diego County's main municipal sexually transmitted disease (STD) clinic had high azithromycin MICs: three with 8µg/mL and two with 16 µg/mL. This report summarizes the laboratory and epidemiologic findings associated with this reduced susceptibility to azithromycin. In San Diego County, clinicians treating cephalosporin-allergic patients with a 2 g dose of azithromycin for uncomplicated gonorrhea are advised to obtain tests of cure 3 weeks after treatment and to recommend sexual abstinence until a negative test result for gonorrhea is achieved. Continued surveillance for antibiotic resistance and effective control efforts are critical for gonorrhea prevention.